An air lubrication system of an outer installation type has good efficiency. An air recovering device includes a recovery side chamber provided on a bottom of a ship on a stern side from an air ejecting device which supplies air bubbles to the ship bottom. The recovery side chamber includes air intake holes formed in a portion of the recovery side chamber opposite to the ship bottom through a gap. The air recovering device also includes a recovering section recovering air inside a recovery side chamber. The air bubbles acquired from the air intake holes are accumulated inside the recovery side chamber to generate pushing pressure so that air can be smoothly recovered from the recovering section.
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8. A ship comprising:
an air ejecting device supplying air bubbles to a bottom of the ship; and
an air recovering device which comprises:
a recovery side chamber provided at an outer surface of a bottom of the ship, said recovery side chamber configured to receive the air bubbles ejected from said air ejecting device, and said recovery side chamber comprising a bottom surface opposite to the bottom of the ship, said bottom surface having an air intake hole; and
a recovering section discharging air inside said recovery side chamber through an air recovery hole formed in the bottom of the ship.
1. An air recovering device comprising:
a recovery side chamber provided at an outer surface of a bottom of a ship so as to project outwardly from the bottom of the ship, said recovery side chamber configured to receive air bubbles ejected from an air ejecting device which supplies the air bubbles to the bottom of the ship, and said recovery side chamber comprising a bottom surface opposite to the bottom of the ship, said bottom surface having an air intake hole; and
a recovering section discharging air inside said recovery side chamber through an air recovery hole formed in the bottom of the ship.
11. A method of modifying a ship which comprises an air ejecting device to supply air bubbles to a bottom of the ship, the method comprising:
installing recovery side chambers at an outer surface of the bottom of the ship so as to project outwardly from the bottom of the ship, wherein each of the recovery side chambers comprises a bottom surface opposite to the bottom of the ship, each of the bottom surfaces having an air intake hole; and
forming a recovering section which is configured to discharge air inside each of the recovery side chambers through an air recovery hole formed in the bottom of the ship.
2. The air recovering device according to
3. The air recovering device according to
wherein said air recovery hole is arranged nearer to a stern of the ship than said air intake hole, and
wherein said recovery side chamber comprises an air accumulating section extending in a longitudinal direction of the ship to accumulate the air acquired from said air intake hole such that the accumulated air is discharged through said air recovery hole.
4. The air recovering device according to
5. The air recovering device according to
6. The air recovering device according to
wherein said recovery side chamber comprises a flat portion having said bottom surface, a front end portion having a slope, and a rear end portion having a slope,
wherein a first end of said front end portion is connected to said flat portion and a second end of said front end portion is connected to the bottom of the ship, and
wherein a first end of said rear end portion is connected to the bottom of the ship and a second end of said rear end portion is connected to said flat portion.
7. The air recovering device according to
wherein said recovery side chamber comprises a narrowing section at a downstream side of said recovery side chamber, and
wherein said air recovery hole is arranged right above said narrowing section.
9. The ship according to
wherein said air recovery hole is arranged nearer to a stern of the ship than said air intake hole, and
wherein said recovery side chamber comprises an air accumulating section extending in a longitudinal direction of the ship to accumulate the air acquired from said air intake hole such that the accumulated air is discharge through said air recovery hole.
10. The ship according to
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The present invention relates to a technique of supplying air bubbles to reduce a resistance between a ship and water. This application claims a priority based on Japanese Patent Application No. JP 2010-216137 filed on Sep. 27, 2010 and the disclosure therein is incorporated herein by reference.
As a technique of improving an efficiency of navigation of a ship, an air lubrication system is known. The air lubrication system is a technique for supplying air bubbles to an outer plate of the ship below a water line to reduce the friction between the ship and water and further improving the efficiency of the navigation. The technique described in JP 2009-248831A is its one example.
The inventor of the present invention is developing a technique of modifying an existing ship to install the air lubrication system externally to improve the efficiency of the navigation. In such a technique, it is demanded that the modification is easy and the reduction of frictional resistance is effective.
In a view of the present invention, an air recovering device includes a recovery side chamber provided on a bottom of a ship on a stern side from an air ejecting device which supplies air bubbles to the ship bottom, and having air intake holes formed in a portion of the recovery side chamber opposite to the ship bottom; and a recovering section recovering air inside the recovery side chamber.
In another view of the present invention, the recovering section is arranged in a different position from the air intake holes in a longitudinal direction of said ship.
In another view of the present invention, the recovering section recovers the air inside the recovery side chamber through an air recovery hole formed in the ship bottom on the stern side from the air intake holes. The recovery side chamber includes an air accumulating section extending in the longitudinal direction to accumulate the air acquired from the air intake holes such that the accumulated air is recovered through the air recovery hole.
In another view of the present invention, the air intake holes are distributed in a wider area in a width direction of the ship than said air recovery hole.
In a view of the present invention, a ship includes: an air recovering device installed in the ship bottom on the stern side from the air ejecting device; and the air ejecting device.
In a view of the present invention, a method of modifying a ship which includes an air ejecting device to supply air bubbles to a bottom of the ship, includes: installing recovery side chambers in the ship bottom on a stern side from the air ejecting device, wherein each of the recovery side chambers includes air intake holes in a portion of the recovery side chamber opposite to the ship bottom; and forming a recovering section which recovers air inside the recovery side chamber.
According to the present invention, an air recovering device, an air lubrication system and a method of modifying a ship in which the reduction of frictional resistance is effective.
Moreover, according to the present invention, in the air lubrication system that an existing ship is modified to install the air lubrication system externally, an air recovering device, an air lubrication system and a method of modifying a ship are provided.
The above-mentioned objects, other objects, effects and features of the present invention will be clarified by the descriptions of the embodiments in linkage with the attached drawings.
Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.
The air ejecting device 7 contains ejecting side chambers 9 arranged on the ship bottom 4, a pipe system 10 and a compressor 11. A blower may be used instead of the compressor 11. The compressor 11 ejects the air inside the pipe 10 to the direction of the ship bottom 4. One end of the pipe 10 is connected to an air supply hole (that will be described later) formed in an outer plate of the ship bottom 4. The ejecting side chamber 9 is attached to the ship bottom 4 in a position in which the air supply hole is formed, by welding or tightening bolts. The air inside the pipe 10 is supplied to the ejecting side chamber 9 by the compressor 11.
The air recovering device 8 contains recovery side chambers 12 and a pipe 13. One end of the pipe 13 is connected to an air recovery hole (that will be described later) formed in the outer plate of the ship bottom 4. The recovery side chamber 12 is attached to the ship bottom 4 in a position in which the air recovery hole is formed, by welding or tightening bolts. The air inside the recovery side chamber 12 is discharged through the pipe 13 to the outside or again supplied to the pipe 10 on the side of the air ejecting device 7.
In examples of
In examples of
The configuration of the ejecting side chamber 9 will be described below.
The front end 22 is a plate-shaped member for connecting the ship bottom 4 and the end of the flat portion 21 on the bow 2 side. The front end 22 has a slope that approaches the ship bottom 4 toward the side of the bow 2, in order to decrease the resistance of water flow when the hull 1 navigates forwardly. The rear end 23 is a plate-shaped member for connecting the ship bottom 4 and the end of the flat portion 21 on the side of the stern 3. The rear end 23 has a slope that approaches the ship bottom 4 toward the side of the stern 3, in order to suppress the generation of eddy that serves as resistance when the hull 1 navigates forwardly and further smoothly guide the air bubbles to the ship bottom 4. The side plate 21-1 closes an opening formed from the ship bottom 4, and the portside portion of each of the flat portion 21, the front end 22 and the rear end 23. The side plate 21-2 closes an opening formed from the ship bottom 4 and the starboard side portion of each of the flat portion 21, the front end 22 and the rear end 23. An air bubble chamber 28 is formed by the flat portion 21, the front end 22, the rear end 23, the side plates 21-1 and 21-2 and the ship bottom 4 covered with them. The space of the air bubble chamber 28 communicates with the water under the ship through air ejecting holes 26 and also communicates with a pipe 10 through an air supply hole 27. The space of the air bubble chamber 28 other than the air ejecting holes 26 and the air supply hole 27 is closed.
In the design of the ejecting side chamber 9, the air bubble chamber 28 is divided into an air scattering section 24 as a region on the side of the bow 2, and an air ejecting section 25 as a region on the side of the stern 3, as shown by a dotted line on the flat portion 21 of
The air supply hole 27 is formed at that position of the ship bottom 4 opposite to the air scattering section 24 which is differing from the air ejecting holes 26 (a position on the side of the bow 2 in
The air, which is supplied from the air supply hole 27 to the air bubble chamber 28, is impinged on the upper surface (inner wall surface) of the flat portion 21 due to a pressure given by the compressor 11. The supplied air is changed into the fine air bubbles due to the pressure of this impingement, and the width of a distribution is easily widen. While the air bubbles are pushed toward a downstream side inside the air scattering section 24, its distribution is expanded in a width direction.
Since the air scattering section 24 is provided, the width of the air supply hole 27 can be made smaller than the width of the air ejecting holes 26 in the width direction of the hull. In other words, by providing the air scattering section 24, the air ejecting holes 26 can be formed to be distributed in the width direction of the hull 1, even when the number of air supply holes 27 is small (one in an example of
A diffusion member can be further added to the ejecting side chamber 9 to diffuse the air bubbles. For example, a porous plate is provided between the air supply hole 27 and the air ejecting holes 26 to partition the air bubble chamber 28 in the longitudinal direction of the hull 1. Consequently, the finer air bubbles can be supplied to the air ejecting holes 26.
When a certain quantity of air bubbles are accumulated inside the air bubble chamber 28, the air bubbles 40 are ejected into the water under the ship bottom 4 from the air ejecting holes 26. When the ship sails, the hull 1 moves in the forward direction against the water. The water flow has a main direction from the front end 22 of the ejecting side chamber 9 to the rear end 23 on the ship bottom 4. On the contrary, since the inner space of the ejecting side chamber 9 is relatively closed, the flows of the water and air in the air bubble chamber 28 are slow, as compared with the external water flow. For this reason, when the air is ejected from the air bubble chamber 28 through the air ejecting holes 26, the air is sheared into the finer air bubbles 40 by shearing force of the external water flow and sent to the downstream side. Since a time period for which the air bubbles 40 stay on the ship bottom 4 is long, the high air lubrication effect is attained. In this way, without being supplied in its original state to the ship bottom 4, via the rear end 23 and the like, the air from the air supply hole 27 once stay in the air bubble chamber 28, and then the air is supplied to the outside so that the shearing force acts against the air. Thus, the air bubbles 40 suitable for the air lubrication are obtained.
Through the design of the shape of the air ejecting hole 26, the air bubbles 40 can be ejected more smoothly from the air bubble chamber 28 into water flows whose speeds are different in the longitudinal direction of the hull 1. In an example of
The structure of the recovery side chamber 12 will be described below.
The front end 32 is a plate-shaped member to connect the ship bottom 4 and the end of the flat portion 31 on the side of the bow 2. The front end 32 has a slope that approaches the ship bottom 4 toward the side of the bow 2, in order to decrease the resistance of the water flow when the ship sails. The rear end 33 is a plate-shaped member to connect the ship bottom 4 and the end of the flat portion 31 on the side of the stern 3. The rear end 33 has a slope that approaches the ship bottom 4 toward the side of the stern 3, in order to suppress the generation of the eddy that serves as the resistance when the hull 1 sails. The side plates 31-1 and 31-2 close side openings by the right and left sides of the recovery side chamber 12, similarly to the side plates 21-1 and 21-2 of the ejecting side chamber, and thus, the air bubble chamber 38 is formed. The air bubble chamber 38 has a space which communicates with the water under the water surface when the ship floats, through air intake holes 36 and also communicates with the pipe 13 through an air recovery hole 37, and a portion of the air bubble chamber 38 other than them is closed. The recovery side chamber 12 having such a structure can be attained by providing the ejecting side chamber 9 on the ship bottom 4 in an opposite orientation in the longitudinal direction of the hull 1.
In the design of the recovery side chamber 12, the flat portion 31 is divided into an air intake section 34 as a region on the side of the bow 2, and a pushing pressure generating section 35 as a region on the side of the stern 3, as shown by a dotted line on the flat portion 31 of
The air recovery hole 37 is formed on at a position of the ship bottom 4 opposite to the pushing pressure generating section 35. One end of the pipe 13 is connected to the air recovery hole 37. By the pushing pressure generating section 35, the air bubble chamber 38 can be provided to have a certain degree of a volume. The air bubbles acquired from the air intake holes 36 stay in the air bubble chamber 38. Since the air bubbles once stay in the pushing pressure generating section 35, the air of some quantity is accumulated in the air bubble chamber 38. As a result, the air bubbles can be smoothly recovered from the air recovery hole 37.
In order to suppress the resistance of the water, the thickness of the recovery side chamber 12 is desired to be thin. When the length of the pushing pressure generating section 35 is set long, the sufficient volume of the air bubble chamber 38 can be attained even if the recovery side chamber 12 is thin. For this reason, for example, similarly to the ejecting side chamber 9, a distance between the center of the air intake hole 36 and the center of the air recovery hole 37 is desired to be set longer than the width of the air bubble chamber 38.
By providing a guide plate 39 in the recovery side chamber 12, it is possible to smoothly acquire the air bubbles 40. The guide plate 39 is provided inside the recovery side chamber 12 to overlap with the air intake holes 36 when viewing from the lower side. The guide plate 39 is provided to approach the ship bottom 4 in a direction from the side of the bow 2 to the side of the stern 3 in an inclined state. By the guide plate 39, the air bubbles 40 acquired from the air intake holes 36 are smoothly sent to the pushing pressure generating section 35.
When the existing ship is modified to install the air lubrication system in the present embodiment, the air supply hole 27 and the air recovery hole 37 are formed in the ship bottom 4. The pipe 10, the pipe 13 and the compressor 11 are provided within the ship. The ejecting side chambers 9 and the recovery side chambers 12 are provided in the ship bottom 4. In this way, it is possible to improve the efficiency of the navigation of the existing ship. Even when the air lubrication system in the present embodiment is installed for a ship to be newly manufactured, the air lubrication system can be installed under few design changes, in accordance with the similar procedure.
The structure of the air lubrication system in the present embodiment is effective in case of using only the air recovering device 8. For example, similarly to the newly-manufactured ship that contains the air lubrication system, an inner installation type ship is employed in which the chamber for ejecting the air bubbles is formed inside the hull 1 and the recovery side chamber 12 is attached from the outside. Even in this case, the same effect as the present embodiment can be attained in the air recovering device 8.
As mentioned above, the present invention has been described by referring to the embodiments. However, the present invention is not limited to the above-mentioned embodiments. Various modifications can be performed on the above-mentioned embodiments. For example, any combination of the above-mentioned embodiments in a range without any conflict with each other can be also considered to belong to the embodiment of the present invention.
Takano, Shinichi, Kawakita, Chiharu, Higasa, Seijiro, Mizokami, Shuji, Kawabuchi, Makoto
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Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Mar 29 2011 | Mitsubishi Heavy Industries, Ltd. | (assignment on the face of the patent) | / | |||
Dec 10 2012 | TAKANO, SHINICHI | MITSUBISHI HEAVY INDUSTRIES, LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 029509 | /0784 | |
Dec 10 2012 | MIZOKAMI, SHUJI | MITSUBISHI HEAVY INDUSTRIES, LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 029509 | /0784 | |
Dec 10 2012 | HIGASA, SEIJIRO | MITSUBISHI HEAVY INDUSTRIES, LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 029509 | /0784 | |
Dec 10 2012 | KAWAKITA, CHIHARU | MITSUBISHI HEAVY INDUSTRIES, LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 029509 | /0784 | |
Dec 10 2012 | KAWABUCHI, MAKOTO | MITSUBISHI HEAVY INDUSTRIES, LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 029509 | /0784 | |
Jan 01 2018 | MITSUBISHI HEAVY INDUSTRIES, LTD | MITSUBISHI SHIPBUILDING CO , LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 046718 | /0352 |
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